Electronic instruments, computer peripheral devices, and similar products are often housed in an enclosure comprising two pieces, for example a top and a bottom, that are joined. Screws are commonly used to join the two enclosure pieces. For plastic molded enclosures, screws typically require metal inserts which in turn require an additional manufacturing step. In addition, in a high volume automated production environment, screws are relatively time consuming and require relatively expensive equipment.
Plastic molded parts may also be designed to be snapped together. Features may be molded into one part that snap into corresponding features molded into another part. Snap fit parts are typically easy to assemble. However, the features may require substantially increased complexity in the plastic molds, requiring tighter tolerances and additional time to tune the molds to ensure that the parts are held precisely and securely. In addition, snap together parts may be difficult to disassemble for troubleshooting or changes after assembly, possibly requiring a tool or fixture to disengage multiple snap features. Finally, it is relatively difficult to design snap together parts with a high retention force. It is particularly difficult to design snap together parts that can survive the shake, vibration and drop requirements of many commercial consumer products.
There are many ways of holding two parts together. Many of these ways function satisfactorily, but are not aesthetically acceptable for some consumer products. For example, various clamping devices are used for enclosures in harsh environments, such as automobile engine compartments, that function very well but may not be generally acceptable for use on a consumer product where appearance is important.
There is an ongoing need for enclosures having ease of automated assembly, ease of disassembly, low tooling cost, low part cost, pleasing aesthetics, and a capability to withstand rigorous vibration and mechanical shock.